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[PATCH v8 00/22] Automatic Disk Unlock with TPM2


From: Gary Lin
Subject: [PATCH v8 00/22] Automatic Disk Unlock with TPM2
Date: Tue, 16 Jan 2024 17:20:38 +0800

GIT repo for v8: https://github.com/lcp/grub2/tree/tpm2-unlock-v8

This patch series is based on "Automatic TPM Disk Unlock"(*1) posted by
Hernan Gatta to introduce the key protector framework and TPM2 stack
to GRUB2, and this could be a useful feature for the systems to
implement full disk encryption.

To support TPM 2.0 Key File format(*2), patch 1~6 are grabbed from
Daniel Axtens's "appended signature secure boot support" (*3) to import
libtasn1 into grub2. Besides, the libtasn1 version is upgraded to
4.19.0 instead of 4.16.0 in the original patch.

Patch 7 adds the document for libtasn1 and the steps to upgrade the
library.

Patch 8~12 are Hernan Gatta's patches with the follow-up fixes and
improvements:
- Converting 8 spaces into 1 tab
- Merging the minor build fix from Michael Chang
  - Replacing "lu" with "PRIuGRUB_SIZE" for grub_dprintf
  - Adding "enable = efi" to the tpm2 module in grub-core/Makefile.core.def
- Rebasing "cryptodisk: Support key protectors" to the git master
- Removing the measurement on the sealed key
  - Based on the patch from Olaf Kirch <OKir@suse.com>
- Adjusting the input parameters of TPM2_EvictControl to match the order
  in "TCG TPM2 Part3 Commands"
- Declaring the input arguments of TPM2 functions as const
- Resending TPM2 commands on TPM_RC_RETRY
- Adding checks for the parameters of TPM2 commands
- Packing the missing authorization command for TPM2_PCR_Read
- Tweaking the TPM2 command functions to allow some parameters to be
  NULL so that we don't have to declare empty variables
- Only enabling grub-protect for "efi" since the TPM2 stack currently
  relies on the EFI TCG2 protocol to send TPM2 commands
- Using grub_cpu_to_be*() in the TPM2 stack instead of grub_swap_bytes*()
  which may cause problems in big-indian machines
- Changing the short name of "--protector" of "cryptomount" from "-k" to
  "-P" to avoid the conflict with "--key-file"
- Supporting TPM 2.0 Key File Format besides the raw sealed key
- Adding the external libtasn1 dependency to grub-protect to write the
  TPM 2.0 Key files

Patch 13~16 implement the authorized policy support.

Patch 17 implements the missing NV index mode. (Thanks to Patrick Colp)

Patch 18 improves the 'cryptomount' command to fall back to the
passphrase mode when the key protector fails to unlock the encrypted
partition. (Another patch from Patrick Colp)

Patch 19~20 fix the potential security issues spotted by Fabian Vogt.

Patch 21~22 add the TPM key unsealing testcase.

To utilize the TPM2 key protector to unlock the encrypted partition
(sdb1), here are the sample steps:

1. Add an extra random key for LUKS (luks-key)
   $ dd if=/dev/urandom of=luks-key bs=1 count=32
   $ sudo cryptsetup luksAddKey /dev/sdb1 luks-key --pbkdf=pbkdf2

2. Seal the key
   $ sudo grub-protect --action=add \
                       --protector=tpm2 \
                       --tpm2key \
                       --tpm2-keyfile=luks-key \
                       --tpm2-outfile=/boot/efi/boot/grub2/sealed.tpm

3. Unseal the key with the proper commands in grub.cfg:
   tpm2_key_protector_init --tpm2key=(hd0,gpt1)/boot/grub2/sealed.tpm
   cryptomount -u <SDB1_UUID> -P tpm2

(*1) https://lists.gnu.org/archive/html/grub-devel/2022-02/msg00006.html
(*2) https://www.hansenpartnership.com/draft-bottomley-tpm2-keys.html
(*3) https://lists.gnu.org/archive/html/grub-devel/2021-06/msg00044.html

v8:
- Introducing TPM device support to grub-emu and adding the TPM key
  unsealing testcase

v7:
- Stopping reading SRK from the well-known persistent handle (TPM2_SRK_HANDLE,
  i.e. 0x81000001) by default since the persistent handle may be created
  by other OS and causes unsealing failure due to SRK mismatching
  - The user now has to specify the persistent handle with "--srk"
    explicitly.
- Utilizing grub_error() to print more error messages 
- Unifying the format of the error messages from TPM2 commands

v6:
- Supporting more SRK types than RSA2048 and ECC_NIST_P256
- Documenting SHA512 as the supported PCR bank type in the tpm2
  protector
- Removing the redundant error message for grub_tpm2_protector_srk_get()
  since it may overwrite the real error message.
- Updating the supported SRK types and PCR bank types in grub-protect 
- Removing the unused type: TPM2_ECC_CURVE

v5:
- https://lists.gnu.org/archive/html/grub-devel/2023-08/msg00113.html
- GIT repo: https://github.com/lcp/grub2/tree/tpm2-unlock-v5
- Rebasing to the latest git HEAD and improving the commit messages
- Implementing authorized poilcy support
- Implementing NV index mode
- Improving the 'cryptomount' command to fall back to the passphrase
  mode when the key protector fails to unlock the encrypted partition
- Fixing the potential security issues

v4:
- https://lists.gnu.org/archive/html/grub-devel/2023-04/msg00104.html
- GIT repo: https://github.com/lcp/grub2/tree/tpm2-unlock-v4
- Improving the error condition checks in cryptodisk.c
- Moving the code to unseal with the standalone policy sequence below
  the code for authpolicy sequence
  - The standalone policy sequence was mistakenly prepended to to the
    authpolicy sequence with grub_list_push() while it should be
    appended.
- Pushing the error messages from the authpolicy sequence into the
  grub_error stack so that we can list all errors from the sequence
- Improving the error messages in the TPM2 protector
- Amending the calculation of the max string lengths of 'Policy',
  'CommandCode' and 'CommandPolicy'
- Skipping the error path in grub_tpm2key_get_authpolicy_seq() on
  success to avoid freeing the authpolicy sequence

v3:
- https://lists.gnu.org/archive/html/grub-devel/2023-04/msg00055.html
- GIT repo: https://github.com/lcp/grub2/tree/tpm2-unlock-v3
- Adding the document for libtasn1
- Improving the error condition checks
  ex: "if (!ptr)" ==> "if (ptr == NULL)"
      "if (err)" ==> "if (err != GRUB_ERR_NONE)"
      "if (rc)" ==> "if (rc != TPM_RC_SUCCESS)"
- Supporting the "TPMPolicy" and "TPMAuthPolicy" sequence in the TPM 2.0
  key File
- Refactoring the key recover function to support "TPMPolicy" and
  "TPMAuthPolicy" sequence
- Using TPMS_PCR_SELECTION_SelectPCR() to set the PCR bit mask
  - Also dropping TPM2_PCR_TO_SELECT() and TPM2_PCR_TO_BIT() which are
    not necessary anymore
- Removing the redundant variable, 'crd', from
  grub_cryptodisk_scan_device_real()
- Fixing the spaces/tabs in cryptodisk.c
- Fixing the comment format in cryptodisk.h
- Adding the defensive check for "cargs->protectors" in
  grub_cryptodisk_scan_device()
- Improving 'grub-protect' for the better support of TPM 2.0 Key File
- Adding more comments
v2:
- https://lists.gnu.org/archive/html/grub-devel/2023-03/msg00094.html
- GIT repo: https://github.com/lcp/grub2/tree/tpm2-unlock-v2
v1:
- https://lists.gnu.org/archive/html/grub-devel/2023-02/msg00130.html
- GIT repo: https://github.com/lcp/grub2/tree/tpm2-unlock

Daniel Axtens (6):
  posix_wrap: tweaks in preparation for libtasn1
  libtasn1: import libtasn1-4.19.0
  libtasn1: disable code not needed in grub
  libtasn1: changes for grub compatibility
  libtasn1: compile into asn1 module
  test_asn1: test module for libtasn1

Gary Lin (9):
  libtasn1: Add the documentation
  tpm2: Add TPM2 types, structures, and command constants
  tpm2: Add more marshal/unmarshal functions
  tpm2: Implement more TPM2 commands
  tpm2: Support authorized policy
  cryptodisk: wipe out the cached keys from protectors
  diskfilter: look up cryptodisk devices first
  tpm2: Enable tpm2 module for grub-emu
  tests: Add tpm2_test

Hernan Gatta (5):
  protectors: Add key protectors framework
  tpm2: Add TPM Software Stack (TSS)
  protectors: Add TPM2 Key Protector
  cryptodisk: Support key protectors
  util/grub-protect: Add new tool

Patrick Colp (2):
  protectors: Implement NV index
  cryptodisk: Fallback to passphrase

 .gitignore                                    |    2 +
 Makefile.util.def                             |   35 +
 configure.ac                                  |    9 +
 docs/grub-dev.texi                            |   27 +
 grub-core/Makefile.am                         |    1 +
 grub-core/Makefile.core.def                   |   44 +
 grub-core/disk/cryptodisk.c                   |  183 +-
 grub-core/disk/diskfilter.c                   |   35 +-
 grub-core/kern/emu/main.c                     |   11 +-
 grub-core/kern/emu/misc.c                     |   51 +
 grub-core/kern/protectors.c                   |   75 +
 ...asn1-disable-code-not-needed-in-grub.patch |  311 ++
 ...tasn1-changes-for-grub-compatibility.patch |  209 ++
 grub-core/lib/libtasn1/COPYING                |   16 +
 grub-core/lib/libtasn1/README.md              |   98 +
 grub-core/lib/libtasn1/lib/coding.c           | 1433 ++++++++++
 grub-core/lib/libtasn1/lib/decoding.c         | 2504 +++++++++++++++++
 grub-core/lib/libtasn1/lib/element.c          | 1110 ++++++++
 grub-core/lib/libtasn1/lib/element.h          |   42 +
 grub-core/lib/libtasn1/lib/errors.c           |  103 +
 grub-core/lib/libtasn1/lib/gstr.c             |   74 +
 grub-core/lib/libtasn1/lib/gstr.h             |   50 +
 grub-core/lib/libtasn1/lib/int.h              |  221 ++
 grub-core/lib/libtasn1/lib/parser_aux.c       | 1179 ++++++++
 grub-core/lib/libtasn1/lib/parser_aux.h       |  172 ++
 grub-core/lib/libtasn1/lib/structure.c        | 1227 ++++++++
 grub-core/lib/libtasn1/lib/structure.h        |   46 +
 .../tests/CVE-2018-1000654-1_asn1_tab.h       |   32 +
 .../tests/CVE-2018-1000654-2_asn1_tab.h       |   36 +
 .../libtasn1_wrap/tests/CVE-2018-1000654.c    |   61 +
 .../lib/libtasn1_wrap/tests/Test_overflow.c   |  138 +
 .../lib/libtasn1_wrap/tests/Test_simple.c     |  207 ++
 .../lib/libtasn1_wrap/tests/Test_strings.c    |  150 +
 .../libtasn1_wrap/tests/object-id-decoding.c  |  116 +
 .../libtasn1_wrap/tests/object-id-encoding.c  |  120 +
 .../lib/libtasn1_wrap/tests/octet-string.c    |  211 ++
 .../lib/libtasn1_wrap/tests/reproducers.c     |   81 +
 grub-core/lib/libtasn1_wrap/wrap.c            |   26 +
 grub-core/lib/libtasn1_wrap/wrap_tests.c      |   75 +
 grub-core/lib/libtasn1_wrap/wrap_tests.h      |   38 +
 grub-core/lib/posix_wrap/limits.h             |    1 +
 grub-core/lib/posix_wrap/stdlib.h             |    8 +
 grub-core/lib/posix_wrap/sys/types.h          |    1 +
 grub-core/tpm2/args.c                         |  177 ++
 grub-core/tpm2/buffer.c                       |  145 +
 grub-core/tpm2/module.c                       | 1127 ++++++++
 grub-core/tpm2/mu.c                           | 1069 +++++++
 grub-core/tpm2/tcg2-emu.c                     |   52 +
 grub-core/tpm2/tcg2.c                         |  143 +
 grub-core/tpm2/tpm2.c                         | 1185 ++++++++
 grub-core/tpm2/tpm2key.asn                    |   31 +
 grub-core/tpm2/tpm2key.c                      |  447 +++
 grub-core/tpm2/tpm2key_asn1_tab.c             |   41 +
 include/grub/cryptodisk.h                     |   16 +
 include/grub/emu/misc.h                       |    5 +
 include/grub/libtasn1.h                       |  645 +++++
 include/grub/protector.h                      |   48 +
 include/grub/tpm2/buffer.h                    |   65 +
 include/grub/tpm2/internal/args.h             |   41 +
 include/grub/tpm2/internal/functions.h        |  174 ++
 include/grub/tpm2/internal/structs.h          |  761 +++++
 include/grub/tpm2/internal/types.h            |  384 +++
 include/grub/tpm2/mu.h                        |  367 +++
 include/grub/tpm2/tcg2.h                      |   34 +
 include/grub/tpm2/tpm2.h                      |   34 +
 include/grub/tpm2/tpm2key.h                   |   83 +
 tests/test_asn1.in                            |   12 +
 tests/tpm2_test.in                            |  179 ++
 tests/util/grub-shell.in                      |    6 +-
 util/grub-protect.c                           | 1492 ++++++++++
 70 files changed, 19289 insertions(+), 43 deletions(-)
 create mode 100644 grub-core/kern/protectors.c
 create mode 100644 
grub-core/lib/libtasn1-patches/0001-libtasn1-disable-code-not-needed-in-grub.patch
 create mode 100644 
grub-core/lib/libtasn1-patches/0002-libtasn1-changes-for-grub-compatibility.patch
 create mode 100644 grub-core/lib/libtasn1/COPYING
 create mode 100644 grub-core/lib/libtasn1/README.md
 create mode 100644 grub-core/lib/libtasn1/lib/coding.c
 create mode 100644 grub-core/lib/libtasn1/lib/decoding.c
 create mode 100644 grub-core/lib/libtasn1/lib/element.c
 create mode 100644 grub-core/lib/libtasn1/lib/element.h
 create mode 100644 grub-core/lib/libtasn1/lib/errors.c
 create mode 100644 grub-core/lib/libtasn1/lib/gstr.c
 create mode 100644 grub-core/lib/libtasn1/lib/gstr.h
 create mode 100644 grub-core/lib/libtasn1/lib/int.h
 create mode 100644 grub-core/lib/libtasn1/lib/parser_aux.c
 create mode 100644 grub-core/lib/libtasn1/lib/parser_aux.h
 create mode 100644 grub-core/lib/libtasn1/lib/structure.c
 create mode 100644 grub-core/lib/libtasn1/lib/structure.h
 create mode 100644 
grub-core/lib/libtasn1_wrap/tests/CVE-2018-1000654-1_asn1_tab.h
 create mode 100644 
grub-core/lib/libtasn1_wrap/tests/CVE-2018-1000654-2_asn1_tab.h
 create mode 100644 grub-core/lib/libtasn1_wrap/tests/CVE-2018-1000654.c
 create mode 100644 grub-core/lib/libtasn1_wrap/tests/Test_overflow.c
 create mode 100644 grub-core/lib/libtasn1_wrap/tests/Test_simple.c
 create mode 100644 grub-core/lib/libtasn1_wrap/tests/Test_strings.c
 create mode 100644 grub-core/lib/libtasn1_wrap/tests/object-id-decoding.c
 create mode 100644 grub-core/lib/libtasn1_wrap/tests/object-id-encoding.c
 create mode 100644 grub-core/lib/libtasn1_wrap/tests/octet-string.c
 create mode 100644 grub-core/lib/libtasn1_wrap/tests/reproducers.c
 create mode 100644 grub-core/lib/libtasn1_wrap/wrap.c
 create mode 100644 grub-core/lib/libtasn1_wrap/wrap_tests.c
 create mode 100644 grub-core/lib/libtasn1_wrap/wrap_tests.h
 create mode 100644 grub-core/tpm2/args.c
 create mode 100644 grub-core/tpm2/buffer.c
 create mode 100644 grub-core/tpm2/module.c
 create mode 100644 grub-core/tpm2/mu.c
 create mode 100644 grub-core/tpm2/tcg2-emu.c
 create mode 100644 grub-core/tpm2/tcg2.c
 create mode 100644 grub-core/tpm2/tpm2.c
 create mode 100644 grub-core/tpm2/tpm2key.asn
 create mode 100644 grub-core/tpm2/tpm2key.c
 create mode 100644 grub-core/tpm2/tpm2key_asn1_tab.c
 create mode 100644 include/grub/libtasn1.h
 create mode 100644 include/grub/protector.h
 create mode 100644 include/grub/tpm2/buffer.h
 create mode 100644 include/grub/tpm2/internal/args.h
 create mode 100644 include/grub/tpm2/internal/functions.h
 create mode 100644 include/grub/tpm2/internal/structs.h
 create mode 100644 include/grub/tpm2/internal/types.h
 create mode 100644 include/grub/tpm2/mu.h
 create mode 100644 include/grub/tpm2/tcg2.h
 create mode 100644 include/grub/tpm2/tpm2.h
 create mode 100644 include/grub/tpm2/tpm2key.h
 create mode 100644 tests/test_asn1.in
 create mode 100644 tests/tpm2_test.in
 create mode 100644 util/grub-protect.c

Range-diff against v7:
 1:  0a5bf6746 =  1:  dcda63b50 posix_wrap: tweaks in preparation for libtasn1
 2:  ef1fd31fb =  2:  9f3ca3e25 libtasn1: import libtasn1-4.19.0
 3:  5e935cf7a =  3:  543b5b4f7 libtasn1: disable code not needed in grub
 4:  4ca0af563 =  4:  01c6f8a5e libtasn1: changes for grub compatibility
 5:  badba7660 =  5:  89cb4a6e8 libtasn1: compile into asn1 module
 6:  736e42762 =  6:  95296156f test_asn1: test module for libtasn1
 7:  c33ccdb3c =  7:  1de592e66 libtasn1: Add the documentation
 8:  14416084f =  8:  f9e763584 protectors: Add key protectors framework
 9:  6cea227ca =  9:  675137af0 tpm2: Add TPM Software Stack (TSS)
10:  2a63876ca = 10:  62866697f protectors: Add TPM2 Key Protector
11:  180d766e4 = 11:  526e31f28 cryptodisk: Support key protectors
12:  1116bc4b9 = 12:  b5a5f3648 util/grub-protect: Add new tool
13:  ec30bb3e5 = 13:  3258119bb tpm2: Add TPM2 types, structures, and command 
constants
14:  00aadc9db = 14:  369fba234 tpm2: Add more marshal/unmarshal functions
15:  4f7c385a8 = 15:  dfa4668f2 tpm2: Implement more TPM2 commands
16:  542c4fc6e = 16:  0c47dd034 tpm2: Support authorized policy
17:  18ede7507 = 17:  3f07bcb61 protectors: Implement NV index
18:  6f89e2dbf = 18:  af122d6af cryptodisk: Fallback to passphrase
19:  e17a0baf5 = 19:  8ef3bab8c cryptodisk: wipe out the cached keys from 
protectors
20:  1c4f7bcd9 = 20:  4e1a6ead5 diskfilter: look up cryptodisk devices first
 -:  --------- > 21:  59df654a0 tpm2: Enable tpm2 module for grub-emu
 -:  --------- > 22:  8b8c69b95 tests: Add tpm2_test
-- 
2.35.3




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